FR2847972A1 - HEAT EXCHANGER AND DEVICE FOR PRODUCING HOT WATER - Google Patents

Abstract

The present invention relates to a heat exchanger and to a device for the domestic production of domestic hot water, comprising an enclosure (5) inside which this exchanger is installed. This device is remarkable in that the exchanger comprises a coil (69) thermally good conductor, wound in a helix, in which the sanitary water to be heated is intended to circulate, each turn (62) of the coil (69) having radial faces (620) which are spaced from the radial faces ( 620) of the turn (62) adjacent to an interstice (L) calibrated by means of a projecting element (64) helical at the same pitch as the coil (69), disposed between the radial faces (620) facing the turns (62), said coil (69) being held between two cylindrical, coaxial shells (65, 66), assembled together at their two ends by two helical flanges (67, 67 '), said primary fluid circulating against the current of sanitary water, between the turns (62) of said coil (69), on either side of said projecting element (64), between said collars (65, 66).

Description

The present invention relates to a heat exchanger and a

  Domestic hot water production device, equipped with such

  exchanger. To satisfy the need for domestic hot water within a dwelling, there are several technical solutions that bring more or less comfort to the user.

  A first solution is to produce hot water with a balloon whose volume can vary from a few tens to a few hundred liters. The reservoir of water accumulated in this flask is heated by an electrical resistance or by a coil through which the fluid of the primary circuit of a heat exchanger of a boiler or fuel oil or gas passes.

  The main advantage of such a balloon is that it allows to have a large flow of hot water as it is not empty, so it is possible to open at the same time several taps in the dwelling.

  However, it occupies a large space in the room where it is installed. In addition, it requires a significant warm-up time if it has been completely emptied and its cost price is expensive.

  A second technical solution is the so-called "instant" production of domestic hot water, that is to say as and when required.

  Figures 1 and 2 attached to this patent application are diagrams that illustrate a domestic installation according to the state of the art, allowing such instantaneous production of hot water.

  This comprises a primary central heating circuit I and a secondary sanitary drawing circuit II, which interferes with each other at a hot water production device D. The latter comprises a small volume balloon B containing a coil S, of circular section, at which heat exchange occurs.

  The primary circuit I comprises a heating source 1 of the water of this circuit; it is for example a boiler provided with a gas burner.

  A suitable pump 15 circulates the water in this circuit I. The water leaves the boiler 1 via a pipe 10, then passes via a "T" -shaped connection R in a pipe 11, passes through the radiators of the heating central 100, and returns to the boiler 1 after dissipating some of its calories in the radiators 100.

  The return pipework comprises two pipes 12, 13 separated by a three-way valve V; the pipe 13 is connected to the boiler 1 after passing through the pump 15 via a pipe 14.

  In this application, the central heating water constitutes the primary fluid; the hot water production device D is connected in parallel with the radiators 100, the bypass being located upstream of these radiators via the "T" connection R and downstream by the three-way valve V. designated by the references a and b the inlet and, respectively, the outlet of the primary fluid inside the hot water production device D. The "T" connection R is connected to the orifice d entered by a line 16; the outlet port b connects to the three-way valve V via a line 17.

  On the secondary circuit II, reference EF has been designated a source of cold water production; it may be for example a tap connected to the drinking water network provided in the dwelling receiving this installation.

  EC has designated a hot water use device; it is for example a faucet or a shower head for supplying hot water to the user.

  The references c and d denote the inlet and, respectively, outlet mouths of the secondary fluid, here the water of the sanitary circuit.

  The source EF is connected to the mouthpiece c via a cold water supply line 19, while the outlet mouthpiece d is connected to the hot water utilization device EC via a dispensing line. hot water 18.

  In the state of the circuits illustrated in FIG. 1, only the primary central heating circuit I is in use.

  The three-way valve V is in a position such that the lines 12 and 13 are placed in communication, the pipe 17 being on the other hand insulated. In this situation, the water supplied by the boiler 1 travels exclusively to the primary circuit I, as symbolized by the arrows F, by heating the radiators 100.

  Figure 2 illustrates the situation in which a water draw is requested, for example by the opening of a valve provided in the EC use device.

  This drawing automatically switches, via an appropriate control system known per se, the three-way valve V, so as to close the outlet of the pipe 12, while on the contrary ensuring the communication of the pipe 17 with the pipe 13.

  Under these conditions, the hot water flowing along the arrow G in the primary circuit I is switched at the "T" connector R to the hot water production device D. It travels the ball B of its entrance a towards its exit b, following a sinuous path through the turns of the coil S. The hot water does not pass in the radiators 100 since the exit of the pipe 12 is closed, but exclusively inside the balloon B and returns to boiler 1 via lines 13 and 14 and pump 15.

  Simultaneously, because of the call for sanitary water, the water of the secondary circuit It travels the coil S of the entry c towards the exit d, as symbolized by the arrows H, that is to say against -current of the water of the primary circuit circulating in the balloon B. The heat exchange takes place between the hot water of the primary circuit present inside the balloon B and the cold water penetrating inside the coil S; it is therefore hot water that reaches the use device EC.

  As an indication, the water leaves the boiler 1 at a temperature of about 80 ° C. and returns to a temperature of between 40 and 600 ° C., depending on the setting of the radiators 100.

  In the secondary circuit II, the cold water penetrating inside the coil S is at a temperature of the order of 150 C and the hot water obtained inside the utilization device EC is at a temperature of in the order of 450 ° C. When the drawing is completed, the three-way valve V switches back to its initial position, which makes it possible to supply the radiators 100.

  The instantaneous flow rate of hot water that can be obtained continuously with such an installation depends on the thermal exchange performance of the device D. However, these are not optimal because the coil S is of circular cross section. As a result, it is impossible to obtain hot water for several faucets at the same time.

  In addition, the coil S tends to scale up quickly.

  In addition, the axial size of a coil of round section is important, so that the dimensions of the balloon B containing it are also.

  In addition, the three-way valve V also has a large footprint.

  Finally, the price of such a valve and its connections and connecting tubes to the device D for producing hot water is important in the total cost of the installation.

  The present invention aims to solve the aforementioned drawbacks.

  It aims in particular to provide a heat exchanger with a large exchange surface, and a hot water production device instantly ensuring a large flow of hot water.

  Another object of the invention is to integrate within the enclosure of the hot water production device a three-way valve system with a very simple structure, so as to substantially reduce the overall cost price. of this device, and to significantly reduce the overall size.

  Yet another object of the invention is to provide a device having a high resistance to the sanitary pressure which can sometimes reach 25 bars (25.105 Pa), these pressure peaks being able in particular to result from "water hammers" or from pressure valves. defective security, for example.

  For this purpose, the invention relates to a heat exchanger comprising a tube of thermally good conductor material, helically wound to form a coil, wherein a fluid, called "secondary", is intended to circulate, this tube having a cross section flattened and substantially oval, the major axis of which is substantially perpendicular to the axis of the helix, each turn of the coil having radial faces which are spaced from the radial faces of the adjacent turn of a gap of constant width, a fluid said "primary" being intended to circulate between each turn of the coil, against the flow of said secondary fluid.

  This exchanger is remarkable in that the gap between two turns 30 adjacent to the coil is calibrated by means of at least one helicoidal projecting element, likewise not the coil and disposed between the radial faces opposite the turns, and in that said coil is held between two cylindrical, coaxial, so-called "internal" and "outer" ferrules, assembled together at each of their two ends by a helical flange whose space between the ends of the coil 35 allows the passage of said fluid primary and its circulation between the turns of said coil on either side of said projecting element, between said ferrules.

  According to other non-limiting features of the invention - said projecting element is stamped into one of the radial faces of the coils of the coil and comes into contact with the radial face of the adjacent turn facing each other; said projecting element consists of a pair of semicylindrical projections embossed in the two radial faces of the turns, each projection of one of the radial faces coming into contact with the projection of the facing radial face; said projecting element is a rigid, helical wire, mounted so that each of its turns is interposed between two adjacent turns of the coil, the opposite small sides of each turn of the coil are brazed with the inner ferrule and the outer ferrule at level of their respective points of contact with them.

  The invention also relates to a domestic production device for domestic hot water which is characterized in that it comprises an enclosure inside which the aforementioned heat exchanger is installed, the sanitary water to be heated constituting the secondary fluid circulating inside the coil, each end of this coil passing through the wall of said chamber at a mouth formed for this purpose, the inlet and the outlet of the primary fluid 20 inside the enclosure through an inlet and an outlet respectively.

  Moreover, according to a certain number of other non-limiting features of the invention, taken alone or in combination: a distribution chamber of the primary fluid is provided inside said enclosure, this chamber being delimited by the wall; interior of the cylindrical inner shell and a circular bottom sealingly closing the end of said inner shell located in the vicinity of the inlet of the secondary fluid, called "inlet end" and an introduction tube of the primary fluid is disposed within said inner ferrule, one of its ends being connected to the inlet of the primary fluid and its opposite end opening at a small distance from said bottom, so that the latter forms a deflector which returns the primary fluid inflow to the opposite end of said distribution chamber; the bottom is concave, its concavity being oriented towards the tube 35 for introducing the primary fluid; - The hot water production device comprises a three-way pipe integrated in said chamber, one of which is formed by the inlet of the primary fluid, the other by an upstream mouth and the third by a downstream mouth, said inlet port being provided with a filter; - This three-way manifold is provided internally, in the vicinity of the inlet port, a deflecting lip for directing the incoming flow of primary fluid, towards said inlet port; the hot water production device comprises a three-way valve for the distribution of the primary fluid, integrated into said chamber, one of the channels of which consists of an outlet orifice of the primary fluid, the other path opens in a downstream mouth and the third opens into an upstream mouth, these two mouths being formed in the wall of the enclosure, this valve comprising a valve adapted to selectively close either said outlet orifice or the channel opening into the upstream mouth ; this valve is mounted on a shaft driven in rotation by a motor; a discharge channel is provided inside the enclosure so as to place the inlet and the primary fluid outlet in fluid communication, this discharge channel being equipped with a discharge valve; the discharge channel is formed between a recess in the enclosure and an intermediate partition disposed between said recess and the outer shell, this discharge channel extending from the vicinity of the upstream end of the enclosure to its downstream end o it opens into the downstream mouth of the three-way valve; the discharge valve comprises a piston biased by a calibrated spring, able to close off a passage orifice for the primary fluid formed in said discharge channel when the pressure of said primary fluid arriving inside the enclosure is less than one predetermined threshold value and which, on the contrary, allows this passage when the pressure exceeds this value; the discharge valve is mounted in a sleeve integral with the recess of the chamber and whose axis is perpendicular to the plane of this recess, the piston being movable in translation along said axis of the sleeve and being urged by a helicoidal compression spring which bears against a dome-shaped piece sealingly attached to said sleeve; the discharge valve comprises a fixed transverse partition separating the space between said recess of the enclosure and the intermediate partition and a base integral with this fixed partition which is traversed on one side by the orifice which can be closed off by said piston and the other by an opening which communicates permanently with the interior of the dome-shaped piece; the enclosure is made of plastic; Finally, the invention also relates to a mixed domestic hot water distribution system comprising a primary central heating circuit and a secondary sanitary drawing circuit, this installation being equipped with a hot water production device such as the one mentioned above, connected in parallel to the radiators of the central heating circuit, the central heating water, supplied by a boiler, constituting said primary fluid and the sanitary drawing water constituting said secondary fluid.

  Other features and advantages of the invention will become apparent on reading the description which will now be made with reference to the accompanying drawings: FIGS. 1 and 2 are diagrams illustrating the operating principle of an installation of mixed heating, equipped with a device for instantaneous domestic hot water production, according to the state of the art; - Figure 3 is an exploded perspective view of the various components of the hot water production device; - Figure 4 is a longitudinal vertical sectional view of the device 20 for producing hot water according to the invention; - Figure 5 is a longitudinal sectional view of the same device, taken along the sectional plane shown by the line V-V in Figure 4; - Figure 6 is a schematic view showing the two rings of the heat exchanger in cross section; FIGS. 7, 8 and 9 are views in transverse vertical section of the device of FIG. 4, according to the sectional planes represented respectively by the lines VII-VII, VIII-VIII and IX-IX of FIG. 4, FIG. 7 further showing the inlet and outlet mouths of serpentine axial section views; Figure 10 is a perspective view of one of the parts of the 3-way valve; - Figure 11 is a perspective view of the downstream end of the hot water production device; FIG. 12 is an enlarged sectional view of the discharge valve of the device of FIG. 4, taken along the section plane represented by the line XII-XII in this figure; - Figures 13 and 14 are sectional views of the same relief valve in the plane of Figure 4, respectively in closed and open positions; - Figure 15 is a top view partially in section of the device of Figure 4; - Figure 16 is a longitudinal vertical sectional view of an alternative embodiment of the hot water production device; - Figure 17 is a diagram of a domestic installation equipped with the hot water production device according to the invention, the latter being shown in section; - Figure 18 is a longitudinal vertical sectional view of an alternative embodiment of the hot water production device; - Figure 19 is a longitudinal sectional view of the same device, taken along the sectional plane shown by the line XIX- XIX in Figure 18; Figure 20 is an end view of the heat exchanger of Figures 18 and 19; - Figure 21 is a diagram partially showing an alternative embodiment of the coil; Figure 22 is a perspective view of the downstream end of the hot water production device shown in Figures 18 and 19; - Figure 23 is a partial longitudinal sectional view of an alternative embodiment of the heat exchanger device shown in Figure 18, the latter being outside the enclosure of the hot water production device; and - Figure 24 is a longitudinal vertical sectional view of an alternative embodiment of the hot water production device shown in Figure 16.

  The heat exchanger 6 will now be described with specific reference to Figures 3, 4 and 5.

  It consists of a tube 69 of flattened cross section and substantially oval, helically wound so as to form a coil, so that the major axis of its cross section is substantially perpendicular to the axis X-X 'of the helix.

  The secondary fluid circulates inside this tube 69 and the primary fluid around it and against the current.

  This tube 69 is made of a thermally good conductive material, preferably metal, for example stainless steel. It consists of a number of turns 62, whose large faces called "radial faces" referenced 620, 621 are spaced from the faces 621, 620 of the adjacent turn 62, a gap of constant width L.

  The short sides of each arc-shaped turn 62 are respectively referenced 624 for the inner side and 625 for the outer side of the coil 69.

  The rectilinear end portions 63, 63 'of this tube extend tangentially outwardly of the helix and terminate in cylindrical end pieces respectively constituting the inlet mouth 60 and the outlet mouth 61 10 of the secondary fluid which circulates. The transition between the flattened portions 63, 63 'and the cylindrical ends 61, 60 is progressively.

  The gap L between two adjacent turns 62 of the coil 69 is calibrated by means of a projecting element.

  According to a first variant embodiment, this protruding element is a round, rigid helicoidal wire 64, likewise not the coil 69 and mounted so that each of its turns 640 is interposed between two adjacent turns 62 of the coil 69. 64 is made of any type of rigid material, for example plastic or metal such as steel.

  The helicoidal wire 64 is interposed between the turns of the coil 69 by screwing. Its role is to prevent deformations of the wall of the flattened tube 69 that may result from variations in the internal pressure. In addition, it makes it possible to keep the gap L constant between two adjacent turns 62, so that the thickness of the primary fluid blade passing between these two turns is also constant, which is essential to obtain a good performance of heat exchange between the primary and secondary fluids.

  The fact of making a coil 69 of flattened section and channeling the primary water flow between the turns and against the flow of the secondary flow makes it possible to ensure a better heat transfer between the two fluids. The size of the coil with flattened turns 69 is thus significantly reduced for better thermal performance.

  The tube or coil 69 and the rigid wire 64 wound helically, are held assembled between two cylindrical coaxial shells, called "internal" and "external" and referenced respectively 65 and 66.

  The expansion efforts of the turns of the tube 69 and the wire 64 are taken up by the presence of these two rings 65, 66, made of a resistant material and preferably thermally good conductor, for example metal, especially steel. The presence of these two thin steel ferrules considerably reduces the thickness of the wall of the coil 69. Thus, to resist without deformation at a pressure of 25 bar (25.105 Pa) inside the coil 69, it suffices that the wall of the latter represents a thickness of 0.5 mm instead of 1.8 to 2 mm for the same section of flattened turn if these ferrules were not present.

  As best seen in FIG. 6, each inner and outer shroud 66 is made from a thin flat sheet rolled on itself to form a cylinder of axis of revolution X-X '.

  This split structure provides some resilience to the shrouds 65, 66 which behave like springs, the inner shroud 65 having a natural tendency to move apart and the outer shroud 66 to close on itself. When assembling the serpentine subassembly 69 / wire 64 inside the ferrules, the outer ferrule 66 is opened slightly while the inner ferrule 65 is wound tighter on itself. After assembly, the two rings 65 and 66 are released and their own resilience brings them back to their original position 20 shown in FIG.

  The two longitudinal ends 650, 660 respectively of each sheet overlap along a generatrix of the cylinder and have a recess located outside the outer shell 66 (respectively inside the inner shell 65) to maintain a constant spacing e between the two ferrules.

  In addition, the inner ferrule 65 and the outer ferrule 66 take up the tensile forces of the wire 64 and the coil 69 by means of two metal flanges or rings (made of steel, for example) 67, 67 ', assembled (preferably by welding) to each of their two ends.

  As shown in FIG. 3, each flange 67, 67 'has a helicoidal general shape with a turn, so that the two ends 674, 675, (674', 675 ') of the turn are not in the same plane and are very slightly offset from each other by a space 676, respectively 676 '. The shape of the ends of the ferrules 65, 66 is adapted accordingly, see FIG. 3, that is to say that it has a small recess 650, respectively 660. As can be seen in FIG. flange 67 has in cross section the shape of a "U" at right angles whose straight central portion 670 is pressed against the radial face 621 of the last turn 62 of the winding 69 and whose two flanges 672 are respectively welded to the outer surface of the inner ferrule 65 and the inner surface of the outer ferrule 66.

  The flange 67 ', located on the right in FIG. 5, has a similar structure.

  The primary fluid enters the heat exchanger 6 tangential to the coil 69, at the level of the space 676, between the first and the second turn of the coil 69, flows on either side of the wire 64 and between the ferrules 65, 66 and spring at the space 676 ', (arrow K, Figure 22).

  Finally, a circular bottom 68 seals the end of the inner shell 65 located in the vicinity of the inlet mouth 60 of the coil 69.

  Preferably, this bottom 68 is concave and its concavity is oriented towards the inside of the shell 65 so as to define a chamber 680.

  According to a second variant embodiment illustrated in FIGS. 18 and 19, the projecting element calibrating the gap L consists of a pair of semicylindrical projections 623, 623 'stamped in the two radial faces 621, 620 of the turns 62. each projection 623 of the radial face 621 contacting the projection 623 'of the radial face 620.

  According to a third variant illustrated in FIG. 21, the projecting element is stamped only on one of the radial faces (here the face 621) of the turns 62 and comes into contact with the radial face 620 of the neighboring turn 62 located opposite . This salient element has the reference 622.

  The two salient elements 622, 623, 623 'which have just been described can be obtained by hydroforming. For this purpose, reference can be made to the document WO-94/16272 describing this technique.

  Finally, according to an alternative embodiment of the invention illustrated in FIG. 23, the inner and outer short portions 624 and 625 of each turn 62 of the coil 69 are brazed at their point of contact respectively with the two inner ferrules 65 and 66. The solders bear the respective references 626 and 627.

  Each solder 626 and 627 is in the form of a helical band extending along the corresponding ferrule.

  The brazing can be carried out by introducing copper powder on the two walls facing inner and outer shrouds 65 65 and then placing the coil 69 and placing the assembly in a vacuum oven.

  The connection between the coil 69 and the two inner and outer shrouds 65 and 66 increases the exchange surface which is in contact with the primary fluid and the secondary fluid and thus substantially increases the overall efficiency of the exchanger while also improving its efficiency. resistance to high health pressure. The rings 65 and 66 behave as a finned surface 10 integral with the coil 69.

  It will be noted that although this is not shown in FIG. 4, it would also be possible to make solders 626 and 627 in the variant where the projecting element calibrating the gap L between two turns 62 is wire 64. however, the latter must be made of metal to withstand the vacuum oven.

  The invention also relates to a device 4 for producing domestic hot water water comprising an enclosure 5 inside which is installed the heat exchanger 6 which has just been described, the sanitary water to be heated constituting the secondary fluid circulating inside the coil 69 of this exchanger.

  Referring now to FIGS. 3, 4, 5 and 7, it can be seen that the enclosure 5 has the general shape of a cylinder whose axis of revolution coincides with the axis XX 'and whose two rounded ends 53, 54 are portions of sphere.

  The end 53 of the enclosure through which the primary fluid is introduced is called "upstream end" and its opposite end 54, "downstream end".

  This enclosure 5 is made of composite material, such as a plastic material loaded for example with fibers or glass flakes, so as to give it mechanical strength properties and low-cost thermal insulation. It consists of two lower half-shells 51 and upper 52, obtained by injection using molds of appropriate shapes.

  The heat exchanger 6 previously described is placed inside the lower half-shell 51 provided with two mouths 510, 511 suitable for respectively receiving the cylindrical ends 60 and 61 of the coil 69, 35 (see Figure 7).

  These tips 60 and 61 are respectively crimped on these mouthpieces 510 and 511, an O-ring 601, respectively 611, sealing between the stainless steel coil 69 and the plastic material of the enclosure 5.

  The upper half-shell 52 is then assembled to form the enclosure 5.

  The tightness is ensured by the hot melting of the edges of the two half-cups 51 and 52, then by underpressure or ultrasonic assembly using a suitable equipment known per se.

  The plane along which the two half-shells 51 and 52 are welded is represented by the line Y-Y '. The X-X 'axis is located in this plane.

  As can be seen in FIG. 4, the outer shell 66 is positioned inside the enclosure 5 by an annular spacer 500 advantageously made of foam. This spacer 500 makes it possible to prevent a flow of parasitic water between the outer shell 66 and the wall of the enclosure 5 Referring again to FIG. 7, it can be seen that the wall 520 of the upper half-shell 52 has a recess 521 extending along the upper generatrix of the cylinder constituting the enclosure 5, parallel to the axis X-X '.

  An element 55 of composite material cooperates with this recess 521 to define a channel 50 whose role will be detailed later.

  This element has the shape of an elongated slightly curved lamella and extends in the cylindrical part of the enclosure 5, between the upstream end 53 at the downstream end 54, (see FIGS. 3 and 4).

  As best seen in FIGS. 7 and 12, this element 55 serving as an intermediate partition is curved so as to lie in the extension of the curvature of the hemi-cylindrical half-shell 52.

  This partition 55 is welded or glued to the wall 520. In accordance with the invention, several hydraulic components necessary for the operation and / or connection of the hot water production device 4 to the rest of the installation are integrated into the enclosure 5, namely a three-way pipe 2, a three-way valve 7, and a discharge valve 8.

  This makes it possible to reduce the number of additional expensive parts and to reduce the total size of the device 4.

  As can be seen in FIGS. 3, 4 and 5, the three channels of the pipe 2 are constituted by a so-called "upstream" mouth 23 formed in the wall of the upper half-shell 52, via a mouth 24, said "downstream", formed in the wall of the lower half-shell 51 and an orifice 20 pierced in a vertical intermediate partition 220, each semi-circular half of which is integral with the corresponding half-shell 51 or 52. This three-piece tubing lanes 2 is formed in the upstream end 55 of the enclosure 5.

  The two mouths 23 and 24 are coaxial axis Z-Z 'perpendicular to the plane YY' and intersecting the axis X-X '.

  The circular inlet 20 is provided with a filter 25 preventing the passage inside the chamber 5 of suspended particles (in particular limestone), present inside the primary water circuit.

  The inlet orifice 20 extends inside the enclosure 5 by a tube 26 for introducing the primary fluid, of cylindrical shape and coaxial with the axis XX 'of the inner shell 65.

  This tube 26 extends from the inlet opening 20 to a short distance from the concave bottom 68, so that the flow of primary liquid entering inside this tube is deflected by the bottom 68 and brought back towards the upstream end 53 of the enclosure (see arrow J).

  The pipe 10 is fitted and then held in the upstream mouth 23 with a not shown clip, the seal being provided by a seal 101, the pipe 1 1 is fitted and then maintained likewise in the mouth 24, The seal being provided by a seal 110.

  The pipes 10 and 11 could also be made integral with these upstream mouths 23 and downstream 24 by any other appropriate means ensuring the seal, (threaded connection etc ....).

  The three-way manifold 2 is further provided with a baffle lip 27 extending inwardly toward the port 20 by locally reducing the inside diameter of said conduit. Its function is to direct the jet of primary fluid against the surface of the filter 25, so as to eliminate in heating mode radiators any impurities that would accumulate during the sanitary heating mode.

  The three-way valve 7 will now be described with reference to FIGS. 4, 5, 8, 9, 10 and 11.

  A complementary piece 700 made of plastic material, the shape of which appears better in FIG. 10, is introduced inside the downstream end 54 of the upper half-shell 52. It has an orifice 70 and an orifice 720 defining the seats. of a valve 75. The orifice 70 is the orifice through which the primary fluid leaves the enclosure 5.

  This complementary piece 700 is arranged so that the orifice 70 extends in a vertical plane and the orifice 720 is located in the extension of a conduit 72, integrally molded with the lower half-shell 51 and extending inside thereof along a longitudinal axis TT 'perpendicular to the plane YY' and intersecting the axis X-X '.

  The conduit 72 opens out of the enclosure 5 at an upstream mouth 73 inside which is fitted and then crimped the pipe 12, the seal being provided by a seal 120.

  The pipe 13 is fitted and then crimped into a downstream mouth 74 of axis T-T ', the seal being provided by a seal 130. This mouth 74 is integral with the upper half-shell 52.

  It will be noted that the channel 50 opens out in the vicinity of the mouth 74 via an orifice 550.

  The three channels of the valve 7 are thus constituted by the outlet orifice 70, by a channel opening into the downstream mouth 74 and by a channel opening into the upstream mouth 73.

  As best seen in FIGS. 4, 5, 8, 9 and 11, a disc valve 75 is mounted eccentrically on a rotary shaft 76 whose axis SS 'is tangent to this valve at a point A. The axis SS' is parallel to the Y-Y 'plane and perpendicular to the X-X' axis.

  The shaft 76 is rotated about the axis SS 'by a motor 77 placed outside the enclosure 5, a rotary joint 78 being formed in the wall of the enclosure 5 for the passage of this shaft . The opposite end of the shaft 76 rests in a bearing 760 formed in the complementary part 700.

  The valve 75 carries a top discode elastic liner 750, able to bear against the edge of the outlet orifice 70, so as to seal it completely leaktight, position shown in dashed lines in Figure 4) and an elastic lining lower discode 751 able to seal the orifice 720, when the shaft 76 is in the position shown in FIGS. 4, 8, 9 and 1.

  The relief valve 8 and its role will now be described in more detail with reference to FIGS. 4 and 12 to 14.

  It may happen at certain times during the operation of the device that all the valves supplying the radiators are partially or completely closed, especially when they are equipped with thermostatic valves.

  The flow rate of the water circulating in the heating circuit is then zero or very low.

  In this case, the main exchanger of the boiler is poorly irrigated with water, which can cause overheating and boiling starts, harmful to its operation and its life.

  To avoid these problems, it is known to mount a discharge valve or "bypass", between the starting line 10 of the boiler and the lines 13 and 14 back to the boiler.

  Such a valve equipped with a calibrated spring, allows the passage of a minimum flow 10 sufficient primary fluid to avoid boiling phenomena, when the flow rate in the installation of the radiators 100 is insufficient or zero.

  According to the invention, this discharge valve 8 is integrated directly into the enclosure 5 of the hot water production device 4.

  The valve 8 is mounted on a substantially cylindrical sleeve 56, 15 of axis W-W 'perpendicular to the axis X-X', integral with the wall of the recess 521.

  The valve 8 comprises a fixed part 80, having the shape of a substantially hemispherical dome, axis W-W ', whose opening is directed downwards.

  The piece 80 is retained inside the sleeve 56 by a ring 83, 20 of the circlip type, the assembly being mounted in a sealed manner, by an elastic annular seal 84, interposed between the elements 80 and 56.

  At its base, the piece 80 rests in a sealed manner on a discode base 57, integral with the recess 521.

  This disc base 57 is pierced by a central circular orifice 58. As best shown in FIG. 13, near the orifice 58 is provided a vertical partition 59. It is substantially tangential to the opening 58. On the other side of the vertical partition 59, with respect to the orifice 58, the discoidal portion 57 is traversed by a second oblong opening 570 (see FIG. 15).

  The valve 8 is provided with a piston 85 having a circular base 86, substantially discode, and an axial rod 87 of axis W-W '.

  The latter is guided in translation, along the axis W-W 'in a tubular sleeve 81 formed in the portion 80 in the form of a dome.

  A helical compression spring 82 constantly tends to push the piston 85 downwards.

  The base 86 of the piston carries an annular elastic seal 860, adapted to bear against the edge of the orifice 58, so as to seal it completely leaktight, when the piston 85 is in the lower position under the stress of the spring 13, as shown in Figures 12 and 13.

  In the absence of drawdown of domestic water, in the case where the radiators are closed or partially closed, there develops a significant overpressure in the channel 50, called "discharge", which will cause the lifting of the piston 85 to against the thrust of the spring 82. This has the effect of releasing the orifice 58.

  In this position illustrated in FIG. 14, the water passes through the orifice 58, penetrates inside the dome 80, exits this space down through the opening 570 and is found on the other side of the chamber. the partition 59, so that it can flow into the discharge channel 50, through the orifice 550 and the mouth 74 to return to the boiler 1.

  The value of the stiffness of the spring 82 is chosen according to the overpressure threshold above which it is desirable for the piston 85 to rise.

  It is also possible to provide directly on the chamber 5, a filling valve connected to the cold water inlet inlet, and also to provide connectors receiving temperature sensors of the various central heating fluids and domestic hot water (not shown).

  FIG. 16 is a simplified representation of an alternative embodiment in which the enclosure 5 is substantially longer than the heat exchanger 6, the length of the tube 26 for introducing the primary fluid being adapted accordingly. This makes it possible to increase the volume of primary hot water present in the vicinity of the heat exchanger 6 and to prevent this primary water from cooling too rapidly when sanitary water is taken and the water cold begins to penetrate the coil 69.

  FIG. 24 illustrates an alternative embodiment of the device of FIG. 16 in which the tube 26 for introducing the primary fluid is not connected to the upstream mouth 23 but is integral with a vertical partition 522, offset in direction of the heat exchanger 6 and integral with the enclosure 5. This partition 522 defines with the left half of the enclosure 5 (with respect to Figure 24), an additional volume of primary water accumulated in reserve.

  The hot water production device 4 is mounted in the mixed central heating and domestic hot water distribution system 35 as shown in FIG. 17.

  The operation of the installation is identical to that described with FIGS. 1 and 2 and the three-way valve 7 makes it possible to select the path of the primary fluid inside the installation. When the primary fluid flows towards the radiators 100, the deflector lip 27 5 locally increases the speed of this fluid, which makes it possible to eliminate the impurities accumulated on the filter 25, especially when this primary fluid is circulating towards the inside of the the enclosure 5.

Claims (19)

  Heat exchanger (6) comprising a tube (69) made of a thermally good conductive material wound helically to form a coil, in which a so-called "secondary" fluid is intended to circulate, said tube (69) having a cross-section that is flattened and substantially oval, whose major axis is substantially perpendicular to the axis (X-X ') of the helix, each turn (62) of the coil (69) having radial faces (620, 621) which are spaced apart from the radial faces (621, 620) of the adjacent turn (62) of a gap (L) of constant width, a so-called "primary" fluid being intended to circulate between each turn (62) of said coil (69), counter-current to the circulation of said secondary fluid, characterized in that the gap (L) between two adjacent turns (62) of the coil (69) is calibrated by means of at least one helicoidal projection element (622, 623, 623 ', 64), as well as the coil (69) and arranged between the radial faces (620, 621) in d each other of the turns (62), and in that said coil (69) is held between two cylindrical, coaxial, so-called "internal" (65) and "outer" shells (66), assembled together at each at both ends thereof by a helical flange (67, 67 '), the gap (676, 676') between the ends (674, 675; 674 ', 675') of the turn allows the passage of said primary fluid and its circulation between the turns (62) of said coil (69) on either side of said projecting element (622, 623, 623 ', 64') between said ferrules (65, 66).   2. Heat exchanger according to claim 1, characterized in that said projecting element (622) is pressed into one of the radial faces (621) of the turns (62) of the coil (69) and comes into contact with the radial face. (620) of the neighbor turn (62) located opposite.   Heat exchanger according to claim 1, characterized in that said projecting element consists of a pair of semicylindrical projections (623, 623 ') pressed into the two radial faces (621, 620) of the turns (62), each protrusion (623, 623 ') of one of the radial faces (621, 620) engaging the protrusion (623', 623) of the facing radial face (620, 621).   4. Heat exchanger according to claim 1, characterized in that said projecting element is a wire (64) rigid, helicodal, mounted so that each of its turns (640) is interposed between two adjacent turns (62) of the coil (69).   5. Heat exchanger according to any one of the preceding claims, characterized in that the small opposite sides (624, 625) of each coil (62) of the coil (69) are brazed with the inner ring (65) and the ferrule external (66) at their respective points of contact (626, 627) with those   Domestic hot water domestic production device (4) characterized in that it comprises an enclosure (5) inside which is installed the heat exchanger (6) according to any one of claims 1 at 5, the sanitary water to be heated constituting the secondary fluid circulating inside the coil (69), each end (60, 61) of this coil (69) passing through the wall of said enclosure (5) at the a mouth (510, 511) provided for this purpose, the inlet and the outlet of the primary fluid inside the enclosure (5) being made respectively by an inlet orifice (20) and a port of output (70).   7. Device according to claim 6, characterized in that a chamber (680) for distributing the primary fluid is formed inside said chamber (5), this chamber (680) being delimited by the inner wall of the cylindrical inner shell (65) and a circular bottom (68) sealingly closing the end of said inner shell (65) in the vicinity of the inlet (60) of the secondary fluid, called "end of "input" and that a tube (26) for introducing the primary fluid 20 is disposed inside said inner shell (65), one of its ends being connected to the inlet port (20). ) of the primary fluid and its opposite end opening at a small distance from said bottom (68), so that the latter forms a deflector which returns the incoming flow of primary fluid to the opposite end of said distribution chamber (680).   8. Device according to claim 7, characterized in that said bottom (68) is concave, its concavity being oriented towards the introduction tube (26) of the primary fluid.   9. Device according to any one of claims 6 to 8, characterized in that it comprises a three-way pipe (2) integrated with said enclosure (5), one of which is constituted by the orifice inlet (20) of the primary fluid, the other through an upstream mouth (23) and the third through a downstream mouth (24), said inlet port (20) being provided with a filter.   10. Device according to claim 9, characterized in that said three-way pipe (2) is provided internally, in the vicinity of the inlet port 35 (20), a deflecting lip (27) for directing the incoming flow of primary fluid to said inlet port (20).   11. Device according to any one of claims 6 to 10, characterized in that it comprises a three-way valve (7) for the distribution of the primary fluid integrated in said enclosure (5), one of which is formed by an outlet (70) of the primary fluid, the other path opens into a downstream mouth (74) and the third opens into an upstream mouth (73), these two mouths (73, 74) being formed in the wall of the enclosure (5), this valve (7) comprising a valve (75) capable of selectively closing either said outlet orifice (70) or the channel opening into the upstream mouth (73).   12. Device according to claim 11, characterized in that said valve (75) is mounted on a shaft (76) rotated by a motor (77).   13. Device according to any one of claims 6 to 1, characterized in that a discharge channel (50) is provided inside the chamber (5) so as to place fluid communication input (20) and the outlet (70) of the primary fluid, said discharge channel (50) being provided with a discharge valve (8). 15 14. Device according to claims 11 and 13, characterized in that the discharge channel (50) is formed between a recess (521) of the enclosure (5) and an intermediate partition (55) disposed between said recess (521). and the outer shell (66), said discharge channel (50) extending from the vicinity of the upstream end (53) of the enclosure to its downstream end (54) where it opens into the mouth downstream (74) of the three-way valve (7).   15. Device according to claim 13 or 14, characterized in that said relief valve (8) comprises a piston (85) biased by a calibrated spring (82), able to close a passage opening (58) of the primary fluid arranged in said discharge channel (50), when the pressure of said primary fluid arriving inside the enclosure (5) is below a predetermined threshold value and which, on the contrary, allows this passage when the pressure exceeds this value .   16. Device according to claim 15, characterized in that said discharge valve (8) is mounted in a sleeve (56) integral with the recess (521) of the enclosure (5) and whose axis (W-W ' ) is perpendicular to the plane of this recess, the piston (85) being movable in translation along said axis (W-W ') of the sleeve (56) and being biased by a helicoidal compression spring (82) which bears against a dome piece (80) sealingly attached to said sleeve (56).   Device according to claims 13, 14, 15 and 16, characterized in that said relief valve (8) comprises a fixed transverse partition (59) separating the space between said recess (521) of the enclosure (5). ) and the intermediate partition (55) and a base (57) secured to this fixed partition (59) which is traversed on one side by the orifice (58) capable of being closed by said piston (85) and another through an opening (570) which communicates continuously with the interior of the dome-shaped piece (80).   18. Device according to any one of claims 6 to 17, characterized in that the enclosure (5) is made of plastic.   19. Mixed domestic domestic hot water distribution system, comprising a primary circuit (1) for central heating and a secondary circuit (II) sanitary draw, characterized in that it is equipped with a device for producing domestic hot water. domestic hot water (4) according to one of claims 6 to 18, connected in parallel with the radiators (100) of the central heating circuit, the central heating water supplied by a boiler (1) constituting said primary fluid and sanitary draw water constituting said secondary fluid.